JP2009123433A - Method of manufacturing control valve type lead-acid battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control valve type lead-acid battery increasing the discharge capacity without decreasing the life performance. <P>SOLUTION: A method of manufacturing the control valve type lead-acid battery in which an electrode plate group having a positive plate, a negative plate and a separator is placed in a battery container has: a step of manufacturing the positive plate by using lead powder and red lead containing 20-80 mass% Pb<SB>3</SB>O<SB>4</SB>as the raw material of a positive electrode active material; and a step of placing the electrode group in the battery container so as to apply pressing force of 9.8-34.3 kPa. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a control valve type lead storage battery.

  In recent years, in order to improve maintainability, a control valve type lead storage battery that adjusts the internal pressure of the battery case with a valve has been widely used. In a control valve type lead-acid battery, an electrode plate group in which a plurality of positive and negative electrode plates are stacked with a separator holding an electrolytic solution in between is arranged in a battery case. At the time of manufacturing, the electrode plate group is compressed without holding the electrolyte solution and placed in the battery case. After the assembly process such as electrode group welding, cell-to-cell connection, lid bonding, terminal welding, etc., it is manufactured through a liquid injection and chemical conversion process. Is done.

  Including such control valve-type lead-acid batteries, adding red lead to the positive-electrode active material of a general lead-acid battery can improve the utilization rate of the positive-electrode active material, thereby enabling the active material required for the same capacity It is known that a battery with a high discharge capacity can be obtained with the same amount of active material.

However, when a general lead (a high lead content of 98% by weight) is added to the positive electrode active material, the bond between the active material particles becomes weak, and the active material is activated by repeated charge and discharge. There was a problem that the softening and detachment of the material was likely to occur and the life was reached early.
As a solution to this problem, for example, a lead storage battery described in Patent Document 1 has been proposed.
Japanese Patent No. 2721514

  According to the invention described in Patent Document 1, by increasing the compression force (hereinafter also referred to as polar group compression force) applied to the electrode plate group of the lead storage battery (for example, 49.0 kPa or more), Softening can be suppressed, and a decrease in the life performance of a battery to which red lead is added as a positive electrode active material material can be suppressed.

However, if the electrode group compression force is increased, the electrolyte solution present between the positive electrode plate and the negative electrode plate is pushed out, the electrolyte solution contained in the separator is reduced, and the discharge capacity of the battery is reduced. If the force is too high, there is a problem that the effect of improving the discharge capacity cannot be obtained.
This invention is completed based on the above situations, Comprising: It aims at providing a control valve type lead acid battery with high discharge capacity, without reducing lifetime performance.

  As a means for achieving the above object, the present invention provides a method for producing a control valve type lead storage battery in which an electrode plate group including a positive electrode plate, a negative electrode plate, and a separator is arranged in a battery case. As a raw material for the active material, a step of producing a positive electrode plate using lead powder and a red lead having a lead oxidation rate of 20% by mass to 80% by mass; A control valve type lead-acid battery manufacturing method comprising: a step of arranging in the battery case so that force is applied.

In the manufacturing method of the control valve type lead-acid battery of the present invention, lead powder and a lead tan with a low lead tanning rate of 20 to 80% by mass are used as the positive electrode active material, and the extreme group compression force. Is 9.8 to 34.3 kPa.
Therefore, according to the present invention, since the polar group pressing force is set lower than that of the lead storage battery described in Patent Document 1, the amount of the electrolyte contained in the separator is increased, so that the polar group pressing force is higher than that having a high polar group pressing force. Discharge capacity increases.

By the way, although it is feared that the effect of suppressing softening and detachment of the active material is lowered when the polar group pressing force is low, according to the present invention, the lead tanning rate is as low as 20 to 80% by mass as lead tan. Since the lead tanning rate is used, the bond between the active material particles is strengthened as compared with the lead storage battery using the high lead tanning rate lead tan with a lead tanning rate of 98% by mass. As a result, it is possible to suppress softening and falling off of the active material caused by setting the polar group compression force to be low.
As mentioned above, according to this invention, discharge capacity can be improved, without reducing the lifetime performance of a control valve type lead acid battery.

A control valve type lead-acid battery (hereinafter also referred to as “battery”) obtained by the production method of the present invention is arranged in a battery case in a state where an electrode plate group consisting of a positive electrode plate, a negative electrode plate, and a separator is pressurized. Battery.
In the present invention, the positive electrode plate of the battery is produced using lead powder and red lead as a positive electrode active material raw material.
Although there is no limitation in particular as lead powder used in this invention, For example, what was manufactured by the ball mill method etc. are used.

The red lead is usually produced by firing at 350 to 450 ° C., and the lead oxidation rate can be adjusted by adjusting conditions such as temperature and time during the firing.
As the lead used in the present invention, for example, a powder obtained by firing the lead powder produced by the above ball mill method at 420 ° C. until reaching a predetermined lead tanning rate can be used.
As the lead used in the present invention, it is preferable to use a lead with a low lead tanning rate from the viewpoint of improving the life performance. The tanning rate is preferably 20% by mass or more and 80% by mass or less.

In the present specification, the minium rate refers to the percentage of Pb ₃ O ₄ of the burned material in when Nica lead by baking lead powder (mass%), baking in particular It is represented by a value obtained by multiplying the value obtained by dividing the mass of Pb ₃ O _{4 in} the product by the mass of the fired product by 100.
The lead oxidation rate, that is, the content (% by mass) of Pb ₃ O ₄ in the fired product can be quantified by the following titration operation.
First, an acetic acid-ammonium acetate solution and a 0.1N sodium thiosulfate solution are added to a measurement sample and stirred to be completely dissolved.
Next, a starch solution is added to this sample solution, and a 0.1N iodine solution is dropped, and the sodium thiosulfate ions remaining in the solution are taken as the end point when a purple color is exhibited by the iodine starch reaction. Titrate. A blank experiment is performed in the same manner, and the Pb ₃ O ₄ content (% by mass) is calculated from the amount of the iodine solution used for the titration using the following formula.
Pb ₃ O ₄ content (% by mass) = [0.3428 × (b′−b) × f] / S × 100
b ′: Amount of iodine solution consumed during titration in the blank experiment (ml)
b: Amount of iodine solution consumed for titration of sample (ml)
f: Factor of iodine solution S: Amount of sample (g)
In the present invention, the amount of added lead is preferably 10% by mass to 30% by mass with respect to the total mass of the positive electrode active material raw material made of a mixture of lead powder and red lead. This is because if the amount of lead is less than 10% by mass, the effect of improving the discharge capacity is hardly exhibited, and if it exceeds 30% by mass, the life performance is lowered.
In this invention, a well-known thing can be used as a negative electrode plate, a separator, and a battery case.

Next, the manufacturing method of the lead acid battery of this invention is demonstrated concretely.
First, as a positive electrode active material raw material, a positive electrode plate is produced using lead powder and lead tan having a lead tanning rate of 20% by mass to 80% by mass. Specifically, lead powder and red lead are mixed and kneaded with water and sulfuric acid to prepare a positive electrode active material paste. After filling this positive electrode active material paste into a lead alloy lattice, it is aged and dried. An unchemically formed positive electrode plate is produced.

Next, an electrode plate group is produced by alternately combining the positive electrode plate and the negative electrode plate produced by a conventional method via a separator. Next, the electrode plate group is inserted into the battery case so that a pressing force of 9.8 to 34.3 kPa is applied.
After inserting the electrode plate group into the battery case under pressure, the electrode plate group is welded, the cells are connected, the lid is bonded, the terminals are welded, the assembly is completed, and dilute sulfuric acid is injected into the battery case. A control valve type lead acid battery is obtained by forming.

  In the present invention, the polar group compressive force is set to 9.8 to 34.3 kPa because if the polar group compressive force is less than 9.8 kPa, the softening and falling off of the active material cannot be suppressed due to insufficient compressive force. This is because if the pressure exceeds 0.3 kPa, the electrolyte between the positive and negative electrodes is pushed out and the electrolyte contained in the separator is reduced, so that a sufficient discharge capacity cannot be obtained.

<Example>
Examples to which the present invention is specifically applied will be described below.
(1) Preparation of positive electrode plate for lead-acid battery A positive electrode active material raw material was prepared by mixing lead powder and lead powder produced by ball milling at 420 ° C. until the predetermined lead tanning rate was reached. .
This positive electrode active material raw material was kneaded with water and dilute sulfuric acid to prepare a positive electrode active material paste, which was filled in a lead alloy lattice, and then aged and dried to prepare an unformed positive electrode plate. For comparison, a positive electrode plate using only lead powder was also produced (used as a positive electrode plate for batteries of test numbers 1, 7, 13, 19, and 25).
In addition, the details of the lead oxidation rate of the red lead used in the production of the positive electrode plate and the addition amount of the red lead relative to the positive electrode active material raw material (a mixture of lead powder and red lead) are shown in each example group.

(2) Production of battery An unformed positive electrode plate produced in (1) and a negative electrode plate produced by a conventional method are alternately combined through a separator to produce an electrode plate group. After inserting into the battery case so as to apply the extreme group pressure, the battery assembly is completed, and diluted sulfuric acid with a specific gravity of 1.20 (20 ° C) is injected and charged to 250% of the theoretical capacity of the positive electrode active material. Chemical conversion was performed to produce a 12V50Ah control valve type lead acid battery. When adjusting the polar group compression force, a spacer was used as necessary. Details of the electrode group pressing force of the fabricated battery are shown in each example group.
In addition, the calculation method of the polar group compression force of the battery produced in the Example group is as follows.
First, a positive electrode plate and a negative electrode plate in a dry state are laminated via a separator to obtain an electrode plate group. Next, both planes of the outermost electrode plate of the electrode plate group are sandwiched in parallel using a smooth plate having a larger surface area than the electrode plate, and perpendicular to the plate sandwiching the electrode plate group using a press machine from the outside. Pressure was applied so that the thickness of the electrode plate group would be the same width as the inside dimension of the battery case to be inserted, and the load at that time was divided by the surface area of the electrode plate group to calculate the electrode group pressing force. In the embodiment, an ABS resin plate is used as a plate sandwiching the electrode plate group, but the material is not limited to this as long as it is strong enough not to be deformed by the pressing pressure when pressed. The polar group compression force was calculated in kgf / dm ² and converted to SI units and expressed in kPa.

<Battery performance evaluation test>
About the battery produced by said method, the battery performance test was done in the following procedures.
(1) 10 hour rate discharge capacity test (capacity test)
In accordance with JIS C 8704-2-1, a 10 hour rate discharge capacity was measured at a room temperature of 25 ° C. with a discharge current of 5.0 A and a discharge start voltage of 1.8 V / cell.
The 10-hour rate discharge capacity of each battery is shown as the discharge capacity ratio when the 10-hour rate discharge capacity of the conventional battery of test number 25 is 100. A larger discharge capacity ratio indicates a higher discharge capacity.

(2) Cycle life test (life test)
The battery was discharged at a room temperature of 25 ° C. with a discharge current of 0.2 CA for 2.5 hours and charged with a charge voltage of 2.4 V / cell (maximum current value of 0.2 CA) for 8 hours, which was one cycle. .
The test was completed when the terminal voltage at the time of discharge was confirmed every 10 cycles, when the terminal voltage became 1.8 V / cell or less, and the number of cycles at that time was defined as the number of life cycles. A larger life cycle number indicates a higher life performance.

  If the life cycle number was larger than the life cycle number (450) of the battery of test number 55, it was judged that the life performance was high. The battery of test number 55 was used as a criterion for determining the life performance for the following reason.

The battery of Test No. 55 uses a mixture of 20% by mass of 98% by mass of lead tanning as the battery positive electrode active material material, thereby improving the discharge capacity and reducing the polar group compression force to 49%. This battery is proposed in Patent Document 1 in which life performance is improved by setting the pressure to 0.0 kPa.
The discharge capacity is higher than that of the test number 25 battery with no lead tin added (lead lead free, 49.0 kPa), and the battery with test number 55 (98% by weight of 20% lead lead added) If the life performance is higher than the pole group compression force (49.0 kPa), it is considered that the object of the present invention is achieved. Therefore, the battery with the test number 55 was used as the evaluation standard for the life performance.

<Example group 1>
In order to investigate the influence of the lead oxidation rate and the electrode group pressure on the discharge capacity and life performance, the positive electrode was prepared by mixing various lead addition rates with lead powder in various addition amounts. A 12V50Ah battery having test numbers 1 to 80 was prepared by applying various pressing forces to the electrode plate group in the battery case using a plate, and a capacity test and a life test were performed.
In Tables 1-3, along with the test results, the lead oxidation rate and the addition amount of the used red lead, and the extreme group pressure were shown.

(1) Discharge capacity (a) Effects of lead tans Between batteries with the same extreme group pressure and whether or not lead tan was added as a positive electrode active material material (for example, test numbers 2 to 6 and tests) No. 1, test numbers 8-12 and test number 7, test numbers 14-18 and test number 13), and the discharge capacity ratios were compared.
As shown in Tables 1 to 3, except for batteries having a polar group compression force of 49.0 kPa, batteries with a lead tanning rate of 20% by mass or more added with a lead tan are more than batteries without any lead tanning. The discharge capacity ratio was high.

  This is because, in a battery to which red lead is added as a positive electrode active material raw material, the utilization rate of the positive electrode active material can be improved, thereby reducing the amount of active material used and having a high discharge capacity. It is thought that can be obtained.

In addition, the discharge capacity ratio increased as the lead tanning rate of the added lead tan increased, but in the case of a battery using a lead tan with a lead tanning rate of 5% by mass, the battery and discharge capacity without any lead tan were added. The result that the ratio was the same was obtained, and the discharge capacity improvement effect by lead-tan addition was not acquired.
From the above, it is considered preferable to use a lead oxide having a lead oxidation rate of 20% by mass or more as a positive electrode active material raw material because a battery having a high discharge capacity can be obtained.

(B) Effect of polar group compression force Discharge capacity ratio between batteries (for example, test numbers 3, 9, 15, 21, and 27) having the same lead oxidation rate and the same amount of lead tan and different polar group compression forces. In comparison, the discharge capacity ratio decreased as the polar group pressing force increased.

  In particular, the discharge capacity ratio of the battery with a polar group compression force of 49.0 kPa is the same as that of the conventional battery (test number 25) except for the one using 98% by weight of lead dantan, which improves the discharge capacity. The effect was not obtained.

This is because when the electrode group pressing force of the lead storage battery increases, the electrolyte present between the positive electrode plate and the negative electrode plate is pushed out, and the electrolyte contained in the separator disposed between the two electrode plates decreases. This is considered to be because a sufficient discharge capacity cannot be obtained if the polar group compression force becomes too high.
From the above, it can be considered that a pole group pressing force of 34.3 kPa or less is preferable because a battery having a high discharge capacity can be obtained.

(C) Summary From the above, a battery with a high discharge capacity can be obtained if a lead tanning rate of 20% by mass or more is added as a positive electrode active material raw material and the polar group pressing force is 34.3 kPa or less. I understood it.

(2) Life performance battery having a lead tanning ratio of 20% by mass to 80% by mass as a positive electrode active material raw material and a polar group compression force of 9.8 kPa or more (test numbers 9 to 11, 15-17, 21-23, 27-29, 37-39, 42-44, 47-49, 62-64, 67-69, 72-74), the life cycle of the battery whose test cycle number is 55 It was greater than the number (450).

This is because the bond between active material particles is reinforced by the use of a lead tan with a lead oxidation rate of 20 to 80% by mass than the lead storage battery of 98 wt. This is thought to be because the softening and falling off of the active material due to the above could be suppressed.
In addition, in the battery (test numbers 1-6, 31-35, 56-60) whose polar group compressive force is less than 9.8 kPa, it is thought that the polar group compressive force was too low to suppress the softening and falling off of the active material. It is done.

  (3) From (1) and (2), a lead tanning rate of 20 to 80% by mass is added as a positive electrode active material raw material, and the extreme group compression force is 9.8 to 34.3 kPa. According to the batteries (test numbers 9-11, 15-17, 21-23, 37-39, 42-44, 47-49, 62-64, 67-69, 72-74) The discharge capacity can be improved without deteriorating the life performance.

<Example group 2>
In order to examine the amount of lead added to the lead powder, batteries with positive plates made by adding various amounts of lead tan are added in various amounts, and their performance was compared. . In this example group, batteries with test numbers 81 to 98 shown in Tables 4 to 6 were newly produced.
A capacity test and a life test were performed on these batteries (test numbers 81 to 98).

  Tables 4 to 6 show the test results and the lead oxidation rate and addition amount of the red lead used, and the extreme group pressure. Moreover, in Tables 4-6, the test numbers 7, 9-11, 13, 15-17, 19, 21-23, 37-39, 42-44, 47-49, 62- conducted in Example group 1 The test results of batteries Nos. 64, 67 to 69, and 72 to 74 are also shown.

(1) About discharge capacity As shown in Tables 4 to 6, the discharge capacity ratio increased as the amount of lead tan was increased, regardless of the amount of dantan.
In particular, when batteries having the same amount of pressure in the polar group are compared with a battery having a lead content of 10% by mass or more and a battery having no lead content added (for example, a test with a test number 9, 37, 62, or 82 battery and a test). Except for the battery of No. 7) and the test No. 15 and the battery of Test No. 42, the difference in the discharge capacity ratio was 2 or more, and the remarkable effect of improving the discharge capacity by adding lead was confirmed.

On the other hand, when the battery with the same amount of pressure in the polar group is compared with a battery with 5% by weight of lead-tan added and a battery without lead-tan (for example, the battery with test number 81 and the battery with test number 7), the discharge capacity The difference in ratio was 0 or 1. From this fact, it is considered that when the amount of added lead is 5% by mass, the effect of improving the discharge capacity due to the addition of lead is not sufficiently exhibited.
From the above, in the present invention, it is considered that the amount of lead red is preferably 10% by mass or more.

(2) Life performance As shown in Tables 4 to 6, the batteries of the present invention (test numbers 9 to 11, 15 to 17, 21 to 23, 37 to 39, 42 to 44, 47 to 49, 62 to 64, 67-69, 72-74, 81-98) was greater than the test number 55 battery (life cycle number 450).

Among these, batteries (test numbers 9-11, 15-17, 21-23, 37-39, 42-44, 47-49, 62-64, 67- 69, 72-74), the number of life cycles was 500 or more, and particularly good results were obtained.
From the above, in the present invention, it is considered that the addition amount of the red lead is preferably 10% by mass or more and 30% by mass or less.

(3) Summary As described above, in the present invention, when the amount of lead oxide in the positive electrode active material material is 10% by mass or more and 30% by mass or less, the battery has high discharge capacity and excellent life performance. Is preferable.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.
(1) In the said Example group, the lead tanning rate of 5, 20, 50, 80, and 98 mass% is used as a lead tan to mix, and the amount of lead tan addition is 5, 10, 20, 30, 40. Although it added to lead powder so that it might become the mass%, the lead tanning rate of a red lead may be 40 mass%, 60 mass%, and 70 mass%, and a lead red addition amount is 15 mass%, 25 It may be mass%.

  (2) In the above-described example group, the batteries in which the polar group compressive force was set to 4.9 kPa, 9.8 kPa, 24.5 kPa, 34.3 kPa, and 49.0 kPa were shown. It may be set to 6 kPa, 29.4 kPa, or the like.

  (3) In the above-described embodiment, the lead powder was produced by firing the lead powder produced by the ball mill method at 420 ° C. until reaching a predetermined lead tanning rate, but produced by other methods such as the Barton method. The lead powder may be fired.

Claims (2)

An electrode plate group comprising a positive electrode plate, a negative electrode plate and a separator is a method for producing a control valve type lead storage battery disposed in a battery case,
As a positive electrode active material raw material, a step of producing a positive electrode plate using lead powder and a lead tan having a lead tanning rate of 20% by mass to 80% by mass;
A step of placing the electrode plate group in the battery case so that a pressing force of 9.8 to 34.3 kPa is applied;
A method for producing a control valve type lead-acid battery, comprising: 2. The method for producing a control valve type lead-acid battery according to claim 1, wherein an addition amount of the red lead is 10% by mass to 30% by mass with respect to the whole positive electrode active material raw material.